MADEMobile Agents based system for Distance Evaluation

Vikram Jamwal

99329009

KReSIT, IIT Bombay

Guide : Prof. Sridhar Iyer

ContentsContents

• The application– Motivation

– Domain

– Existing Schemes

• Distributed system structuring– Prevailing paradigms

– Mobile agent approach

• Mobile agent frameworks• Our model• Experimentation• Conclusions

Distance EvaluationDistance Evaluation

• Emergence of distance education– Need for distance evaluation mechanisms

• Alternatives to paper-based exams– Computer based and Internet based

• Scheduled and uniform exams

Types of e-testing mechanismsTypes of e-testing mechanisms

• Where does the database reside?• Locally

– Computer Based Testing (CBT)– Examples

• GRE and GMAT

• Remote– Internet based testing– Examples

• www.eexam.com• www.netexam.com

• Any Time exams

Computer Based Testing (CBT)Computer Based Testing (CBT)

• Different Question-Paper for each examinee– Generated dynamically

• Adaptive– Different weights given to different questions– Next question decided on the basis of

• difficulty level and • correctness of answer to previous question

Question Bank

Generator

Question Paper

Feedback

Existing Internet Based Testing SchemesExisting Internet Based Testing Schemes

• Front End– Mostly “HTML - form based”– answers sent using ‘GET’ and ‘POST’ methods– Java applets, flash

• Back End– CGI scripts– Java servlets

• Security– Authentication done using ‘login - password’– May use “https” for secure exchange

• Some issues – Web Servers are basically stateless

Important PointsImportant Points

• Existing models are basically– Pull based – Client-Server

• Extending Internet based evaluation techniques– Push model– Different kinds of content– Dynamic organization of content– Off-line examination V/S on-line examination– Subjective answers (not just objective)

• Key technical issues– How to deliver the exam content?– How to evaluate the answers?

• Our solution– Use Mobile Agents

Call to server procedure

DataClient Serverresults

Procedure

DataClient ServerProcedure

Client Server

Code on Demand

DataClient Serverresults

Procedure

Remote Evaluation

Distributed System Structuring MechanismsDistributed System Structuring Mechanisms

DataClient Server

DataServer

DataServer

Procedure+

State

DataServer

Procedure+

State

Procedure+

State

Procedure+

State

Mobile Agents

Procedure+

State

How Mobile Agents Help?How Mobile Agents Help?

• Map directly to real life situations• Need a generic execution environment• Can work in both modes

– push– pull

• Can work off-line• Provide local interactions • Provide multi-hop solutions

DataBase

Desktop

Server

SystemResources

Laptop

User Application Legacy Software

Execution EnvironmentMobile Agent

Service AgentApplication

Agent MigrationLocal Communication

Global Communication

Typical Mobile Agent FrameworkTypical Mobile Agent Framework

MAFsMAFs

• Components– Life Cycle– Navigation – Communication– Security

• Classification basis– Type of migration and code shipping mechanism– Agent tracking and directory service– Resource access control mechanism– Communication

• Local, global, communicating partners

• Systems Surveyed– 50+ frameworks – Notable : Aglets, Concordia, Voyager, Grasshopper, D’Agents, Mole

Voyager - Our ChoiceVoyager - Our Choice

• Better remote messaging• Generalized distributed object computing platform• Compatibility with latest java version• Easy creation of remote objects• Moving objects

– relative and absolute

• Other– Federated directory service– Different kinds of messaging (sync, one-way, future)– Object and agent persistence support– Distributed event handling– Security manager– Compatible with CORBA and DCOM

Examination Process (Three Stages)Examination Process (Three Stages)

• Exam setting– examiners set the question papers

• Distribution and testing– question papers are presented to the students

• Evaluation and result compilation– answers are collected and results compiled

• Design guidelines– Automate as much as possible– Simplify requirements of infrastructure at different ends– Reliability

PS-2

PS = Paper Setter

PS-3

PS-4PS-4

PS-1

Paper Assembler

Comprehensive Paper

= Mobile Agents

To Distribution Server

Examination Setting: OverviewExamination Setting: Overview

NS

N-1

N-2

NS

NS

Cloning

Install Agent

GUI

Fetch Agent

Launcher

Controller GUINS = Name ServerN = Paper Setter Node

Examination Setting: DetailsExamination Setting: Details

Dynamic Upgrade

RemoteSetterGUIFetchAgentInstallAgent

new RemoteSetterGUI()

NamingService

register( )

getGUIName()

addEnhancePanel()

removeEnhancePanel()

new EnhancePanel()

getGUIReference()

Dynamic UpgradationDynamic Upgradation

DistributionServer

Exam Center Distribution

Server

Single copy of paper

c9611060

Separate Copy per user

List of Students enrolled…

…

Each Candidate get a Copy

1

4

3

2

Answered and Returned

5

Each copy returned

Distribution and TestingDistribution and Testing

c9611060

Examiner B

Examiner A

Examiner D

Examiner C

Distributor

Results

……

Agents collaborate to produce the final result

Objective Questions Evaluator

Distribution Server

Evaluation and Result CompilationEvaluation and Result Compilation

Evaluation Center

Examiner –1

Objective Question Evaluator

Distribution Server –1

Paper Coordinator

Question Paper Courier Agent

Student- 1a Student- 1b Student- 2a Student- 2b

Distribution Server –2

Result PublishingServer

Answer Paper Agent

Examiner –2

Stage 2 and 3 : DetailsStage 2 and 3 : Details

Salient Features of the DesignSalient Features of the Design

• Generic execution environments on each machine– Remote code installation

• After distribution and before collection– The students work off-line

• Agent creation by distribution servers– Not student machines

• Workflow between examiners• Automated compilation of results

Measuring Response TimesMeasuring Response Times

050

100150

200250

300350

400450

500

1 2 3 4 5 6 7 8 9 10 11

Request Number

Res

po

se i

n m

illi

seco

nd

Mobile Agent

Client-Server

Student Paper Interface Client

MA Interactions

Client –Server Interactions

Incorporating Dynamic ContentsIncorporating Dynamic Contents

New Level

Old Level

• MQPs can be organized into various skill levels• Once a person has finished one level, a new level

2 can be sent

ConclusionsConclusions

• Mobile Agents provide effective and flexible mechanisms for structuring distributed systems like distance evaluation

• Advantages– Student response times– Handling objective and subjective contents– Application level multicasting– Dynamic upgradation of applications– Support for heterogeneous execution environments– Centralized control and management of logistics and security of

examination process

• Some Issues– Reliability– Persistence– Security– Infrastructures

Questions ?

Thank You